Thermo King Super II SR+, Manual, Page: 66 / 145

Engine Maintenance (Rev 6/98)
56
Engine Thermostat
For the best engine operation, use a 180 F (82 C) thermostat
year-round.
Thermostat
ENGINE FUEL SYSTEM
The fuel system used on the Thermo King se 2.2 diesel
engine is a high pressure distributor (VE type) injection
pump. The governor, timing device, fuel supply and other
components are located within the pump itself.
The components of the fuel system are:
• Fuel tank
• Fuel strainer
• Fuel filter
• Water separator
• Hand fuel pump
1. Jiggle Pin
2. This End Toward Engine
AEA1363
1
2
• Transfer pump
• Injection pump
• Injection nozzles
The hand fuel pump is used to manually draw fuel from the
tank up to the transfer pump if the unit should run out of
fuel.
Operation
Fuel is drawn from the tank by the transfer pump. The trans-
fer pump delivers fuel to the water separator and then to the
fuel filter. The fittings at the top and bottom of the filter
base each contain an orifice. The orifices control the pres-
sure in the fuel system by allowing a certain amount of fuel
to return to the tank. Filtered fuel passes through a line from
the outlet fitting on the filter base to the injection pump.
Fuel enters the injection pump and then a fuel supply pump.
Pressure in the injection pump is set by a relief valve
located in the output of the fuel supply pump and a small
drilled orifice in the outlet banjo bolt on the top of the
pump. Excess fuel is recycled back through the fuel supply
pump. As the engine speed increases, so does the internal
injection pump fuel pressure. The increased pressure moves
a piston which in turn advances the timing of the engine.
The banjo fitting also acts as a transfer point for overflow
fuel coming from the nozzles and a point to bleed air from
the system.
Injection pump leakage, injection nozzle overflow and
excess fuel from the fuel filter orifice are then all sent back
to the fuel tank in the return line.
CAUTION: Do not switch banjo bolts from one
injection pump to another. When calibrating an
injection pump, use the banjo bolt that belongs to that
pump. Using a different banjo bolt after calibration can
affect engine timing.